274 ANATOMY OF THE (,YM NOSPKRMS 



According to experiments reported by Dr. Bovey, as carried out in the 

 testing laboratories at McGill University, the following values may be 

 assigned to Douglas fir : 



Specially selected wood, free from knots and cut out of the log at a 

 distance from the heart, gave 



Coefficient of bending, pounds per square inch . . 9,000 



Coefficient of elasticity in pounds 2,000,000 



Weight per cubic foot 34 



Ordinary first-quality wood gave 



Coefficient of bending, pounds per square inch . . 6,000 



Coefficient of elasticity in pounds 1,430,000 



Weight per cubic foot 34 



The Douglas fir often forms extensive forests to the almost complete 

 exclusion of other species, ranging from sea level to an elevation of 

 nearly 10,000 feet in Colorado, and reaching its greatest development 

 and value in Oregon and Washington (Sargent). 



All parts of Vancouver Island with the exception of the exposed western 

 coast ; near the 49th parallel it ranges from the coast of the mainland 

 to the Rocky Mountains, where it occurs in a stunted form at eleva- 

 tions of 6000 feet ; on the eastern slopes of the Rocky Mountains, 

 from the 49th parallel northward through the Porcupine Hills to the 

 Bow River, where it reaches its eastern extension at Calgary; in 

 the interior of southern British Columbia it is generally confined to 

 the higher uplands between river valleys ; northward it descends to the 

 general level of the country (Macoun); mountain ranges of Washing- 

 ton, Oregon, and the California coast ranges and the Sierra Nevadas; 

 east to Montana, Wyoming, Colorado, and the Guadeloupe Moun- 

 tains of northern and eastern Arizona, and southward into Mexico 

 (Sargent). 



This tree is known but sparingly in the fossil state, the only representa- 

 tive so far known having been derived from the glacial deposits at 

 Mystic Lake, near Bozeman, Montana. The age of these deposits 

 cannot be accurately determined from the present data, but they prob- 

 ably represent the result of glaciation which may have continued for 

 some time after the period of continental glaciation, and even until 

 quite recently. The tree is, however, now extinct in that locality, and 

 it is possible that its elimination may have been due to the same general 

 causes that brought about a withdrawal of Sequoia from the prairie 

 region during glacial time. 



